Overview
Kataoka and colleagues measured cadmium in 180 chocolate products and 140 cocoa powder products sold in Japan. The survey found broad product-level variation: chocolate products ranged from 0.00021 to 2.3 mg/kg cadmium (Cd), while cocoa powder ranged from 0.015 to 1.8 mg/kg Cd. The paper is direct occurrence evidence for cadmium in chocolate and cocoa powder as sold in the Japanese retail market.
Key numbers
| Matrix | n | Cd range | Mean | Median | Maximum | Notes |
|---|---|---|---|---|---|---|
| Chocolate products, total | 180 | 0.00021-2.3 mg/kg | 0.20 mg/kg | 0.12 mg/kg | 2.3 mg/kg | Table 3; includes 140 dark, 35 milk, and 5 white chocolate products. Eight of the 180 chocolate products exceeded the applicable EU maximum levels by the authors’ comparison (4.4%); per Table 2, seven of those eight were dark chocolate and one was milk chocolate. |
| Dark chocolate | 140 | 0.025-2.3 mg/kg | 0.25 mg/kg | 0.15 mg/kg | 2.3 mg/kg | Table 3. |
| Milk chocolate | 35 | 0.012-0.31 mg/kg | 0.043 mg/kg | 0.023 mg/kg | 0.31 mg/kg | Table 3. |
| White chocolate | 5 | 0.00021-0.0016 mg/kg | 0.00059 mg/kg | 0.00028 mg/kg | 0.0016 mg/kg | Table 3. |
| Cocoa powder products | 140 | 0.015-1.8 mg/kg | 0.32 mg/kg | 0.16 mg/kg | 1.8 mg/kg | Tables 3 and 4; 26 of 140 cocoa powder products exceeded the EU maximum level by the authors’ comparison. |
For chocolate products with labeled cocoa-solids content, the authors reported a weak positive association between cadmium concentration and cocoa-solids content. Table 5 grouped those 140 labeled products as <50%, 50% to <70%, 70% to <80%, and >=80% cocoa solids; the 70% to <80% group had the highest reported mean at 0.32 mg/kg Cd.
Methods (brief)
The study purchased 320 retail samples from April 2015 to August 2016, homogenized portions of each product, digested 0.5 g aliquots using nitric acid, hydrogen peroxide, and closed-vessel microwave digestion, and measured cadmium by ICP-MS. The stated limit of quantitation was 0.00005 mg/kg. Method validation used chocolate samples spiked at 0.005, 0.2, and 1.0 mg/kg Cd, with trueness of 101%-103%.
Related evidence
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